Re: 2G memory split

[Mark Lord <mlord@pobox.com>]

Mark Lord wrote:
..
> +choice
> +    depends on EXPERIMENTAL && !X86_PAE
> +    prompt "Memory split"
> +    default VMSPLIT_3G
> +    help
> +      Select the desired split between kernel and user memory.
> +
> +      If the address range available to the kernel is less than the
> +      physical memory installed, the remaining memory will be available
> +      as "high memory". Accessing high memory is a little more costly
> +      than low memory, as it needs to be mapped into the kernel first.
> +      Note that increasing the kernel address space limits the range
> +      available to user programs, making the address space there
> +      tighter.  Selecting anything other than the default 3G/1G split
> +      will also likely make your kernel incompatible with binary-only
> +      kernel modules.
> +
> +      If you are not absolutely sure what you are doing, leave this
> +      option alone!
> +
> +    config VMSPLIT_3G
> +        bool "3G/1G user/kernel split"
> +    config VMSPLIT_3G_OPT
> +        bool "3G/1G user/kernel split (for full 1G low memory)"
> +    config VMSPLIT_2G
> +        bool "2G/2G user/kernel split"
> +    config VMSPLIT_1G
> +        bool "1G/3G user/kernel split"
> +endchoice
> +
> +config PAGE_OFFSET
> +    hex
> +    default 0xC0000000
> +    default 0xB0000000 if VMSPLIT_3G_OPT
> +    default 0x78000000 if VMSPLIT_2G
> +    default 0x40000000 if VMSPLIT_1G
> +
...
>  #ifdef __ASSEMBLY__
> -#define __PAGE_OFFSET        (0xC0000000)
> +#define __PAGE_OFFSET        CONFIG_PAGE_OFFSET
>  #define __PHYSICAL_START    CONFIG_PHYSICAL_START
>  #else
> -#define __PAGE_OFFSET        (0xC0000000UL)
> +#define __PAGE_OFFSET        ((unsigned long)CONFIG_PAGE_OFFSET)
>  #define __PHYSICAL_START    ((unsigned long)CONFIG_PHYSICAL_START)
>  #endif
>  #define __KERNEL_START        (__PAGE_OFFSET + __PHYSICAL_START)

Mmm.. somethings wrong with this version..
I have selected VMSPLIT_2G, but on rebooting the kernel
now only sees/uses 1GB of RAM (the machine has 2GB of RAM).

Almost as if those trailing "if VMSPLIT_" clauses are being ignored.
--
Mark Lord
Real-Time Remedies Inc.
mlord@pobox.com

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